Add performance tuning

Add a diff with and without player in server. The server will tune bot activity to reach the desired server tick speed (in ms), as what CMaNGOS' playerbots are using.

ce4bd79d2d is used as a reference.

src/RandomPlayerbotMgr.cpp

@@ -28,6 +28,7 @@
 #include "ChannelMgr.h"
 #include "Unit.h"
 #include "World.h"
+#include "UpdateTime.h"
 
 #include <algorithm>
 #include <cstdlib>
@@ -79,6 +80,106 @@ void activateCheckPlayersThread()
     t.detach();
 }
 
+class botPIDImpl
+{
+public:
+    botPIDImpl(double dt, double max, double min, double Kp, double Ki, double Kd);
+    ~botPIDImpl();
+    double calculate(double setpoint, double pv);
+    void adjust(double Kp, double Ki, double Kd) { _Kp = Kp; _Ki = Ki; _Kd = Kd; }
+    void reset() { _integral = 0; }
+
+private:
+    double _dt;
+    double _max;
+    double _min;
+    double _Kp;
+    double _Ki;
+    double _Kd;
+    double _pre_error;
+    double _integral;
+};
+
+
+botPID::botPID(double dt, double max, double min, double Kp, double Ki, double Kd)
+{
+    pimpl = new botPIDImpl(dt, max, min, Kp, Ki, Kd);
+}
+void botPID::adjust(double Kp, double Ki, double Kd)
+{
+    pimpl->adjust(Kp, Ki, Kd);
+}
+void botPID::reset()
+{
+    pimpl->reset();
+}
+double botPID::calculate(double setpoint, double pv)
+{
+    return pimpl->calculate(setpoint, pv);
+}
+botPID::~botPID()
+{
+    delete pimpl;
+}
+
+
+/**
+ * Implementation
+ */
+botPIDImpl::botPIDImpl(double dt, double max, double min, double Kp, double Ki, double Kd) :
+    _dt(dt),
+    _max(max),
+    _min(min),
+    _Kp(Kp),
+    _Ki(Ki),
+    _Kd(Kd),
+    _pre_error(0),
+    _integral(0)
+{
+}
+
+double botPIDImpl::calculate(double setpoint, double pv)
+{
+
+    // Calculate error
+    double error = setpoint - pv;
+
+    // Proportional term
+    double Pout = _Kp * error;
+
+    // Integral term
+    _integral += error * _dt;
+    double Iout = _Ki * _integral;
+
+    // Derivative term
+    double derivative = (error - _pre_error) / _dt;
+    double Dout = _Kd * derivative;
+
+    // Calculate total output
+    double output = Pout + Iout + Dout;
+
+    // Restrict to max/min
+    if (output > _max)
+    {
+        output = _max;
+        _integral -= error * _dt; //Stop integral buildup at max
+    }
+    else if (output < _min)
+    {
+        output = _min;
+        _integral -= error * _dt; //Stop integral buildup at min
+    }
+
+    // Save error to previous error
+    _pre_error = error;
+
+    return output;
+}
+
+botPIDImpl::~botPIDImpl()
+{
+}
+
 RandomPlayerbotMgr::RandomPlayerbotMgr() : PlayerbotHolder(), processTicks(0), totalPmo(nullptr)
 {
     playersLevel = sPlayerbotAIConfig->randombotStartingLevel;
@@ -236,6 +337,14 @@ void RandomPlayerbotMgr::UpdateAIInternal(uint32 elapsed, bool /*minimal*/)
     if (!sPlayerbotAIConfig->randomBotAutologin || !sPlayerbotAIConfig->enabled)
         return;
 
+    if (sPlayerbotAIConfig->enablePrototypePerformanceDiff)
+    {
+		LOG_INFO("playerbots", "---------------------------------------");
+		LOG_INFO("playerbots", "PROTOTYPE: Playerbot performance enhancements are active. Issues and instability may occur.");
+		LOG_INFO("playerbots", "---------------------------------------");
+        ScaleBotActivity();
+    }
+
     uint32 maxAllowedBotCount = GetEventValue(0, "bot_count");
     if (!maxAllowedBotCount || (maxAllowedBotCount < sPlayerbotAIConfig->minRandomBots || maxAllowedBotCount > sPlayerbotAIConfig->maxRandomBots))
     {
@@ -327,6 +436,23 @@ void RandomPlayerbotMgr::UpdateAIInternal(uint32 elapsed, bool /*minimal*/)
     }
 }
 
+void RandomPlayerbotMgr::ScaleBotActivity()
+{
+    float activityPercentage = getActivityPercentage();
+
+    //if (activityPercentage >= 100.0f || activityPercentage <= 0.0f) pid.reset(); //Stop integer buildup during max/min activity
+
+    //    % increase/decrease                   wanted diff                                         , avg diff
+    float activityPercentageMod = pid.calculate(sRandomPlayerbotMgr->GetPlayers().empty() ? sPlayerbotAIConfig->diffEmpty : sPlayerbotAIConfig->diffWithPlayer, sWorldUpdateTime.GetAverageUpdateTime());
+
+    activityPercentage = activityPercentageMod + 50;
+
+    //Cap the percentage between 0 and 100.
+    activityPercentage = std::max(0.0f, std::min(100.0f, activityPercentage));
+
+    setActivityPercentage(activityPercentage);
+}
+
 uint32 RandomPlayerbotMgr::AddRandomBots()
 {
     uint32 maxAllowedBotCount = GetEventValue(0, "bot_count");